The present invention relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a hydraulically set concentric packer with multiple umbilical bypass through a piston of the packer.
It has long been desired to provide a convenient and economical method of extending umbilicals (such as hydraulic, electrical and/or fiber optic lines) through packers in subterranean wells. The lines could merely pass through the interior of an inner mandrel of a packer, but then the lines would interfere with flow and access through the packer, and the lines would be exposed to damage from tools, abrasive fluids, etc. passing through the packer.
One proposed solution to this problem is to install a sleeve within the mandrel, and position the lines between the sleeve and the mandrel. The sleeve would protect the lines from damage. Unfortunately, the presence of the sleeve restricts flow and access through the packer.
Another proposed solution is to extend the lines through a sidewall of the inner mandrel or an outer housing of the packer. However, this requires the mandrel or housing to have an increased wall thickness, which reduces the available cross-sectional area in the packer for flow area or, in the case of a hydraulically set packer, for actuator piston area. If the actuator piston area is reduced, then the available setting force is consequently reduced.
To provide sufficient piston area where the lines are extended through the outer housing, the housing may be provided with an eccentric bore (i.e., greater wall thickness on one side as compared to an opposite side of the housing). Unfortunately, this either requires the inner mandrel to be offset to one side in the housing (which in turn causes tubing connected above and below the packer to be laterally offset), or requires that the piston also be eccentrically formed. Each of these is undesirable for operational and/or manufacturing cost reasons.
Therefore, it will be appreciated that there is a need for improved ways of extending lines through packers and through actuators for packers. These improvements could find use in other applications, as well.